Method of staining glass and glass staining composition



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vise-r Patented Dec. 8, 1953 EUNITED STATES PATENT OFFICE s 2,662,037 7 METHOD F STAININ G GLASS AND GLASS if STAININ G COIHPOSITION f r 'Ormonde S. Levi, Toledo, Ohio, assignor to Verd- I corporation of Ohio This invention relates to compositions and methods for staining glass and to the stained glass products thereby produced. More par ticularly, this invention is directed to the staining of soda-lime, borosilicate, lead glasses, and the like, and to the particles produced, such as stained fiat ware, incandescent lamp bulbs stained to reduce the attraction of insects, for

therapeutic or dark room uses, and the like.

This application is a continuation-in-part of my co-pending application Serial No. 153,749 entitled Stained Glass and Method of Staining Same, filed April 3, 1950, now abandoned.

The art of staining to which the present invention is directed comprises the coloration of a,

glass surface, and is not to be confused with colored glass, wherein the molten glass batch to the glass surface to be stained and the article is baked at a predetermined temperature to efiect staining of the glass surface. The excess mud is then removed by washing andscrubbing. Copper salts have been used aloneon borosilicate glass to provide a yellow stain and, upon reduction of the copper, a .red stain. No stain is obtained by copper salt alone on sodalime glass. Copper and silver salts have been used in combination with one another to produce amber stains on soda-lime glass, but these stains are relatively light colored, being much too light for coloring incandescent light bulbs for therapeutic use. Also, the high temperatures required for eiiective staining using this stain composition, may deform the thin bulb as well as metallize the staining ingredients, this latter effect greatly reducing the amount of light and heat transmitted through the bulb.

In spite of the long period in which glass stains have been known and used, and in spite of considerable research upon staining compositions, the art of staining glass has advanced so little since early times that only a very limited number of colors can be obtained by staining, and only particular glass compositions can be used. It is for this reason that the art of staining glass is seldom practiced at the present time.

A-Ray Processing Company, Toledo, Ohio, a

No Drawing. Application May 13, 1953, Serial .No.'354,896

12 Clawims. I (Cl. 117-65) There are definite advantages, however, to staining glassware rather than coloring the entire glass batch as is now the usual practice. In the first place, partially finished glassware may be colored to order. facturers who provide finished articles to color their glassware independently of the operation of the manufacturer who produces the glass;

Also, large colored articles, such as stained glass windows, may be produced in one sheet of glass rather than the multi-pieced leaded windows now made, and at a lower price.

which they are applied.

orating glassware, however, has been restricted due tothe limited number of colors obtainable and inability to control these colors.

'An object of this invention, therefore, is to provide compositions and methods for staining glassin a variety of colors, and thus produce new and improved stained glass articles.

Another object of this invention is to provide compositions and methods for staining glass uniformly and for producing a stain having an accurately predetermined and reproducible color. Still another object of this inventionis to provide compositions and methods for staining 1 several types of glass, such as soda-lime, borosilicate, lead glasses, and the like, in a variety of colors and in varying shades.

A still further object of this invention is'to provide compositions and methods for staining soda-lime glass at temperatures belowthe soft-' ening point of the glass as well as the metalliz ing point of the stain composition, said stains being permanent, uniform and reproducible.

colors which are uniform throughout the stained area.

Still another object of this invention isto" provide an amber lime glass and a method of making it that may be readily employed at a;-

temperature low enough to avoid danger of de-f formation of thin glass, such as the walls of an incandescent lamp bulb, and still produce a deep This permits those manu amber stain satisfactory for therapeutic and dark room purposes.

An additional object of this invention is to provide a method and composition for staining :1 borosilicate glass yellow, for such use as incan- 5 descent bulbs, etc.v I

Still another object of this invention is to prdvide a method for staining glass surfaces which includes the application thereto of a uniform oil dispersion which can be applied by brushing, spraying, screening or dipping, and having such viscosity and spreading characteristics thatit can be applied and fired to produce, glass surfaces stained in a desired pattern. L5;

Other objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description thereof};

THE INVENTION IN GENERAL con rolled by correctly proportion'ing the sta' ns "sred nts' a'ndby areiul'res la on i the has sitempe atures-i i I 'in fbompositions and manipulative steps illii rating thefrnethcdrof the present invention. are setforth thefollpwingexamples:

Example "'1 .'A uniform dispersion was formed by grinding" in a porcelain lined ball mill providedwith porcelainballs the following compofii U Cusp. grams 13 Ages. "gram" .1. ZnS- "grams," 9 'Irichloroacetic acid; do. 7.1; ochre do 80, Screening oil cc Methylalcohol cc 4Q,

The resulting oil dispersion which was of suitable viscosity for d p instw s p lie m la hula n th r su tin cea edibul la d n am fflsn? mimee rd redie a emner i se ab ut 9 i and allowed t .-v Rss slu maiar ing on the surface, ofthe bulb wasthen' washed. f and he bulbw'as f n i ,hara s n ain d 50 ee mmercia a e tab e .919% A procedure identical with that .t .4 s'a ii el .w ir e pt ng; a,,1 6.1 gramportion'of benzyl cl 'loridewa's substituted for the trichlorcacetic acidl: na eeptr ,55 ablefgrayis'hgreenlstain ws pmdueedtj I 7 .Es'dmple 35 A, prceedure identical masher; described Example 1 was carried [out except that an, 11.3 gram portion of dilchloroethyl) fqij ai kcnflocnnci) 2) was; "substitutedffor the trichloroacetic .acid. I A light greenl stained bulb wasprodtces. ;Empze1i;-.-A procedure identical with that describedin Example 1 was carried out ,except; that jan I1 8L8 gram portion "of ethylene 'chlortji 5 bromide was substituted for the" trichloroaceti'c 7 acid K,commerciallyiacceptable green stai' bulbjwas producedj ithas be'erifound 'that'optifriiini results can be achieved according to. the invention either when 7 nosalt of 'copp'er,f silver or "zinc is asulfide}.}or when at least one of these salts is *a' sulfide and; themolecular ratio of sulphur to chlorineis from aboutj 1:.0.5 to about .ijzzaijMost "desirably, at

eas ng the se jf di are sulfides, and the molecular ratio of suliplmf' large anions upon the concentration of the m t component or ion which effects the staining O the glass. .filThus thelcuprous compounds are pferred rather than the cupric because] there is} a of ,c opper in the former than} s;, 0f the strong mineral acids I ,r y tis factory, since the anion portion of the salt is never materially heavier than theg metal'portion; and the sulfides are especially advantageous. The use of chloride salts of copper silrcn and zinc is not claimed herein, but is claimed in a copending application filed concurrently herewith. entitled ..Method of Staining Glass and Glass Staining Composition. ,.The,.

claims of iihe instant, application are limited to.

mate of. organic chloride compounds as the sole sources fo r chlorine l, 1

heco per silver and zinc in the salts of these metals constitute the active staining portionsof their respective. salts in staining methods according to .the'. invention, Therefore, the; irelative. amounts ofthe salts may best be. definedby refer.- ence to the relative percentagesby. weight ofcop per, silver and zinc present, these percentages based upon thetotal weight 'of the three metal ions calculated .as metals.

,Stainmg.. 9mi?0 itions,can be obtained by combining .Qm Ag, and Zn salts in widelyvarying, proportions. ,Thereare no sharplimits delineating omppsitions which will stain glassand compos ns whichlwill not It is essential, however, thatall three ni etal cations be present since the absence of any one is fatal to the improved stain- 111g characteristics.,attained by the combination of the three QWhileIthe minimum amount, calculated as above described. of. each of the. three metal. ions required for staining according to the method of the, invention will vary slightly dependingother, componentsnof the staining compgsition at leastabout 0.815 per vcentof A at least abeutllfi per centofzn,and at least about .qfC a e required toproduce an aca mate ial av n e mpr ved ias s l? stai ing 0 aracteristi c s herein described. The

terms centf and ffparts, are used herein app.ended claims to refer to percent and parts by weight', .unles'sotherwise indicated.

the. o er li i o s.

an he lqweif limit f Cu should be at least about 40 Der cent LBest' cemmercial stains I are pro: th As c nten sfromeb u 2- p. 1 991 1. D ss r hepar de s ze of s f tain ns. in red e t '..,i or ant, s n asr.. ia i ls deimii as, i as thoroughly andunifprmly asdo the smaller parides-i- .j ijcr. mestcfieciire resul s t. is. sual y si'iiristall' inusQSOp 'mesh, U. .S.-Sieve Series.

ions iesielaiesteieiasiearnes ne s 1 t M H 2.5 per ce nt; the lower f Zn should be t least about 20 percent;

' g hat theljparticle sizewofthe, active .r i n n in i orm. 011 d -v tory results, can be achieved particle izeof the material is all minus .calculated as. indicated.

tabllsihed, in part, by the minimals of the other two. but over 21 per cent of Ag has no apparent it. is necessary that at least a certain amount of an organic chloride compound be present, and

that the organic chloride compound be trichloroacetic acid, benzyl chloride, ethylene chlorobromide, o di(chloroethyl) formal, as hereinbefore discussed. The presence of as little as 1.4: per 'centlof chlorine, derived from the organic chloride compound, and based upon the total amount of copper, silver and zinc, calculated as metals, is sufficient to cause the appearance of some green staining. When at least about 2.8 per cent of chlorine, calculated as indicated, is present, a good green stain can be obtained. Additional amounts of chlorine do not produce any material change in the staining properties of the composition other than a slight darkening, until I the amount thereof exceeds about 115 per cent, Chlorine above this percentage may cause etching of the glass and deterioration of the stain color and is, therefore, undesirable. Accordingly, any amount of chlorine. from aboutlxl per centto about 115 per cent, calculated as indicated, .is satisfactory.

Ordinarily, for practical reasons, from about 2.8 per cent to about 2.0 per cent of chlorine is preferred.

Additional. ingredients for stain. composition While the active staining ingredients may be used by themselves to produce a stain-on glass,

much -more satisfactory results are obtained when other ingredients are added. Ochre is useful as'such an additional ingredient, serving to disperse and to dilute the active staining ingredients, as well as to give body to the stain composition to assist in its application to the glass surface.

Ochre isa standard ingredient for most stain compositions, and is both cheap and .readily available. The composition of the ochre usedin the examples set forth herein is as follows:

Percentages V Ferric oxide 52.52 Silica 26.37 Alumina 11.05

Moisture 0.81 Loss on ignition 9.25

The exact composition of the ochre is a matter-of choice, but a particular ochre should be selected and standardized if accurate reproduction of stain colors is to be achieved, since the ochre composition does affect the color of the stain to a certain extent. The amount of dispersing agent will vary with the composition of the active staining ingredients, but must be conmetals, copper, silver and zinc, as the sulfide. Best results are obtained when. all three of the metals, copper, silver and zinc, are added as sulfides, and preferably at least the copper and silver are added as sulfides. Effective staining may be produced, however, without any sulfide present.

I Oil is used in amounts. sunicientto form the staining composition into a slip having the desired consistency. The consistency or' viscosity of the staining slip desired will vary with the intended use. When a flat surface is 'to be stained, a relatively thin or low viscosity slip may be employed satisfactorily. When a curved surface, such as a lamp bulb, is to be stained amore viscous slip must be provided in order to'be retained in a uniform layer upon the surface The amount of oil employed will also vary'considerably with the particular ingredients of stain. For example, much less oilis required to achieve a given viscosity for a stain in which the dispersing agent or ochre has been omitted than in one which contains a large amount of ochre. In addition, if the stain composition is to be used for decorating glassware, as by applying it infa desired pattern to a glass surface, for example, by a silk screen technique, the viscosity of "the staining composition must be controlled within relatively narrow limits so that application is possible, but the stain slurry, after-application,

doe not run or spread from the pattern in which However, unless particular viscosity characteristic are desired of the staining composition it is preferredto use water as the carrier-for the active staining ingredients asdisclosedand claimed in my co-pending application Serial No. 321,275, now abandoned. Accordingly, when'an oil dispersion is employed, this is usually done in order :to achievea particular desired'result with the sta ni g mpo n.uh c 're ult sua l a niques, as described above.

other oilsand even lower petroleum fractions such as gasoline, naphtha and kerosene, alcohols and other volatile solvents can also be employed.

, In any event, the oil that is used should-be one trolled within certain limits, since an extremely Other dispersing 1' der to o n th most d rab e: depths.

of color, it is preferred to add at least one of the 'that'is volatilized at a temperature'below. about 800 F., approximately the minimum .t'emperature at which stainingcan be efiectedaccording tothe invention, as hereinafter described.

' Memes of makin a rjdflcpclyin the sw m composition The variousingredients of the stain composition may be combined by anumber of different procedures, none, of which appears materially'to affe e n n characteri i s oi th resulting composition One procedure which ha .begn

staining composihoninvolves'grindin the variallowed to cool. then be washed and subsequently stained as o'us components of the stain in a ball mill containing porcelain balls. The copper, silver, and zinc salts may be added to the ball mill, followed by approximately half the total amount of oil to be added to the composition. The stain ingredients are then ground, preferably until they will pass through a 200 mesh screen, U. S. Sieve Series, at which time the remaining portion of the oil is added to make a slurry of the desired consistency. The particle size of the active staining ingredientsaffects the staining properties of the composition, as above noted.

The staining composition i applied to the surface of the article to be stained by dipping, spraying, brushing, screening, or the like. The dipping procedure is fast and adaptable to automatic assembly line procedure, but, as above noted, oil dispersions are preferably used when their particular characteristics are desired, for example because silk screening is to be employed. Control of the viscosity of the slurry, in any event, is required in order to obtain a coating of the stain composition of optimum thickness by the particular technique of application being employed. When the stain coating or mud is too thick, cracks form during the baking procedure which ultimately show up in the finished article as unstained lines. If the slurry is too thin, the stain may not be continuous or may be too light because of low concentration of the active staining ingredients. Routine experiment will establish the satisfactory viscosity for any particular operation.

In the baking operation, fairly close control of the temperature of the glass must be maintained to obtain the desired, predetermined color. The temperature employed will be determined in parts by the melting or softening point of the glass being stained, but temperatures in excess of 1100 F. destroy the staining composition by metallizing the copper, silver and zinc salts. Since there is considerable lag in temperature rise between the air in an oven and the glass body, temperature should be taken directly from the glass surface that is being stained. Indirect heating or heating by conduction is preferred to direct heating by radiation, since more uniform heating of all sides of the article to be stained may be obtained. In baking the mud coated article, the article is placed in an oven and heated slowly to a predetermined temperature, such as about 900 F. If the glass article is relatively thin so that no strains will develop, it may then be immediately removed from the oven and allowed to cool in the air. For thicker articles, such as heavy bottles or. flatware, cooling should be gradual. The mud is then removed by washing and brushing the finished stained article obtained. Throughout this specification staining temperatures specified are the temperatures to which the glass surface has been heated, and the abovedescribed staining procedure is employed unless otherwise stated.

For best results in staining aged glass or glass which contains decolorants, such as selenium and antimony, a prebaking process is quite advantageous. The glass surface to be stained is heated to a temperature slightly in excess of that which is to be used in the staining operation and then The heat treated surface may above described. Much deeper stains result when this prebaking step is employed on the aged glass or glass containing decolorants than when theglass is directly stained without this preiliminary step.

Color of stains Stain compositions comprising thepresenlt inof glass surfaces.

stains.

tion. The baking is another factor which may be employed to control the color of the stain. As above indicated, the amount and type of ochre, the type of glass, the presence of sulfides, and the particle size of the active staining ingredients also affect the color of the stain to a lesser degree, and so must be standardized to obtain careful color control and to reproduce a given color.

An amber color stain is obtained when the baking temperature ranges from 800 F. to 925 F., regardless of the particular amounts of the active staining ingredients. When the Ag ion is present in amounts over 21% (of Cu, Zn, Ag total), an amber is obtained at any baking temperature between 800 F. and 1100 F., the upper limit established by the decomposition point of the staining ingredients. With staining compositions containing less than 21% Ag ion, a red or green stain is obtained at baking temperatures between 925 and 1100 F., depending upon the composition of the stain. Red stains may be obtained even with the lower amount of Ag ion, which usually produces a green stain, by carefully maintaining the baking temperature just below 1000" IT, but such a procedure is diificult to follow and mixed colors frequently are obtained.

The predominant factor in controlling the color of the stain is the percentage of thethree metal ions, Ag, Zn and Cu. Less than 1 per cent of silver introduces a green color into the stain, while further additions up to about 8 per cent tend to darken the green color. The transition point from green to red is from about 8 per cent to about 10 per cent of silver, and above 10 per cent of silver but under 21 per cent of silver results in a red stain. Over 21 per cent of silver an amber stain is obtained, even at baking temperatures of 1000 F., and little change is ob-- tained by increasing the silver above this percentage.

While this transition from green to red to amber is true generally of increased amounts of silver, the percentage of silver at which these changes occur will vary somewhat with the ratio of copper to zinc. For example, an increase in percentage of copper with a corresponding decrease in percentage of zinc tends to decrease the redness of a stain produced from a composition containing enough silver for a red stain.

The chemical mechanism which is responsible for staining of glass according to the method of the invention is not understood. It has definitely been established that each element of the combination of active staining ingredients is required, and that only specified organic chloride compounds are satisfactory sources for chlorine. For example, when trichloroethane was substituted for the'trichloroacetic acid used in Example 1, the resulting composition imparted no color whatsoever to glass. Similarly, substitution of propylene dichloride, ethylhexyl chloride,

1 dicliilorfo-ethyl ether, ethylene dichloride, ethylene,-chlorohy'drin, triglycoldichloride, or dichlo roisiopropyl ether for the trichloroacetic' acid of Example 1 resulted in' a composition capable of imparting only a very faint trace of color to glass.

1 Staining diflerent glasses Stain compositions of the present invention are useful; not only in the staining of soda-lime glass, but other types as well, including lead glass, borosilicate glass, etc. Different colors maybe obtained on diiierent types of glasses with the same staining composition.

I claim: p

1. method of staining glasssurfaces which comprises forming a finely divided, uniform oil dispersion containing chlorine-free copper, silver and Zinc salts and an organic chloride compound comprising at least one chlorine attached to a; carbon atom of an aliphatic radical selected from the group consisting of trichloroacetic acid, benzyl chloride, di(chloroethyl) formal, and ethylene chlorobrom'ide in amounts sufficient to stain glass, and in proportions such that, based on'the total amount of copper, silver and zinc present calculated as metals, copper constitutes from about 15 per cent to about 90 per cent, silver at least about 0.875 per cent,'and zinc at least about 1.7 per cent, and chlorine, based on the total amount of copper, silver-and zinc present, calculated as metals, constitutes. at least 1.4 per cent but not more than'about 115 per cent, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 F. to produce a stained glass surface.

2. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing chlorine-free copper, silver and zinc salts and trichloroacetic acid in amounts su'fli'cient to stain glass, and in proportions suchthat, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per cent to about 90 per cent, silver at least about 0.875 per cent, and zinc at least about 1.7 per cent, and chlorine,

based on the total amount of copper, silver and zinc present, calculated as metals, constitutes at least 1.4 per cent but not more than about 115 per cent, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 F. to produce a stained glass surface.

3. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing chlorine-free copper, silver and zinc salts and benzyl chloride in amounts 7 sufiicient to stain glass, and in proportions such that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per cent to about 90 per cent, silver at least about 0.875 per cent, and zinc at least about 1.7 per cent, and chlorine, based on the total amount of copper, silver and zinc present, calculated as metals, constitutes at least 1.4 per cent but not more than about 115 per cent, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 F. to produce a stained glass surface.

4. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing chlorine-free copper, silver and zinc salts and di(ch1oroethy1) formal in amounts sufficient to stain glass, and in propor- 10 tions such that, .based on the total amount. of copper, silver and zinc present, calculated as metals, copper constitutes from about 15 per cent to about per cent, silver at least about 0.875 per cent, and zinc at least about 1.7 per cent, and chlorine, based on the total amount of copper, silver and zinc present, calculated as metals, constitutes at least 1.4 per cent but not more than aboutl15 per cent, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 F. to produce a stained glass surface.

5., A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing chlorine-freecopper, silver and zinc salts and ethylene chlorobromide in amountssufiici'ent to stain glass, and in proportions such that, based on the total amount of copper, silver, and zinc present, calculated as metals, copper constitutes from about 15 per cent to about 90 per cent, silver at least about 0.875 per cent, and zinc at least about 1.7 per cent, and chlorine, based on the total amount of copper, silver and zinc present, calculated as metals, constitutes at least 1.4 per cent but not more than about 'cent, coating a glass surface with said dispersion, and heating the coated glass" surface to atemperature from about 800 F. to about 1'100'F.'to produce a stained glass surface.

6. Ainethod of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing chlorine-free salts of copper, silver andzinc, at least two of which salts are sulfides, and an organic chloride compound comprising at least one chlorine attached to a carbon atom of an aliphatic radical selected from the group consisting of trichloroacetic acid, benzyl chloride, di (chloroethyl) formal, and ethylenecmorobromi'de in'amounts sufficient to stain glass, and in proportions such that, based. on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 15; percent to about 90 per cent, silver at least about 0.875 per cent, and zincat least about 1.7 per cent, and chlorine, based on the total amount of copper, silver and zinc present, calculated as metals, constitutes at least 1.4 per cent but not more than about 115 per cent, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 F. to produce a stained glass surface.

7. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing chlorine-free copper, silver and zinc salts, at least two of which are sulfides, and trichloroacetic acid in amounts suflicient to stain glass, and in proportions such that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 40 per cent to about 85 per cent, silver from about 0.875 per cent to about 21 per cent, and zinc at least about 20 per cent, and chlorine, based on the total amount of copper, silver and zinc present, calculated as metals, constitutes at least.2.8 per cent but not more than about 115 per cent, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 F. to produce a Stained. glass surface.

8. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing chlorine-free copper, silver and zinc salts, at least two of which are sulfides, and benzyl chloride in amounts sufficient to stain glass, and in proportions such that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 40 per cent to about 85 per cent, silver from about 0.875 per cent to about 21 per cent, and zinc at least about 20 per cent, and chlorine, based on the total amount of copper, silver and zinc present, calculated as metals, constitutes at least 2.8 per cent but not more than about 115 per cent, coating a glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 F. to produce a stained glass surface.

9. A method of staining glass surfaces which ,on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 40 per cent to about 85 per cent, silver from about 0.875 per cent to about 21 per cent, and zinc at least about 20 per cent, and chlorine, based on the total amount of copper, silver and zinc present, calculated as metals, constitutes at least 2.8 per cent but not more than about 115 per cent, coating 8, glass surface with said dispersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 F. to produce a stained glass surface.

10. A method of staining glass surfaces which comprises forming a finely divided, uniform oil dispersion containing chlorine-free copper, silver and zinc salts, at least two of which are sulfides, and ethylene chlorobromide in amounts suificient to stain glass, and in proportions such that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes 12 zinc present, calculated as metals;; constitutes at least 2.8 per cent but not more than about 115 per cent, coating a, glass surface {with said-cliepersion, and heating the coated glass surface to a temperature from about 800 F. to about 1100 to produce a stained glass surfacei 11. A composition of matter for staining glass comprising finely divided, uniform1 oil dispersion containing copper, silver anid zinc salts and an organic chloride compound comprisingat leastone chlorine attached to a carbon atom of an aliphatic radical selected from the group'cons'istabout 115 per cent.

from about 40 per cent to about 85 per cent, silver 12. A composition of matter for staining glass comprising a finely divided, uniform oil dispersion containing copper, silver and zinc salts and an organic chloride compound comprising at least one chlorine attached to a carbon atom of an aliphatic radical selected from the group consisting of trichloroacetic acid, benzyl chloride, di(chloroethyl) formal, and ethylene chlorobromide in amounts suflicient to stain glass, and in proportions such that, based on the total amount of copper, silver and zinc present, calculated as metals, copper constitutes from about 40 per cent to about per cent, silver from about 0.875 per cent to about 21 per cent, and zinc at least about 1.7 per cent, and chlorine, based on the total amount of copper, silver and zinc present, calculated as metals, constitutes at least 2.8 per cent but not more than about per cent.

ORMONDE S. LEVI.

No references cited. 

1. A METHOD OF STAINING GLASS SURFACES WHICH COMPRISES FORMING A FINELY DIVIDED, UNIFORM OIL DISPERSION CONTAINING CHLORINE-FREE COPPER, SILVER AND ZINC SALTS AND AN ORGANIC CHLORIDE COMPOUND COMPRISING AT LEAST ONE CHLORINE ATTACHED TO A CARBON ATOM OF AN ALIPHATIC RADICAL SELECTED FROM THE GROUP CONSISTING OF TRICHLOROACETIC ACID, BENZYL CHLORIDE, DI(CHLOROETHYL) FORMAL, AND ETHYLENE CHLOROBROMIDE IN AMOUNTS SUFFICIENT TO STAIN GLASS, AND IN PROPORTIONS SUCH THAT, BASED ON THE TOTAL AMOUNT OF COPPER, SILVER AND ZINC PRESENT, CALCULATED AS METAS, COPPER CONSTITUTES FROM ABOUT 15 PER CENT TO ABOUT 90 PER CENT, SILVER AT LEAST ABOUT 0.875 PER CENT, AND ZINC AT LEAST ABOUT 1.7 PER CENT, AND CHLORINE, BASED ON THE TOTAL AMOUNT OF COPPER, SILVER AND ZINC PRESENT, CALCULATED AS METALS, CONSTITUTES AT LEAST 1.4 PER CENT BUT NOT MORE THAN ABOUT 115 PER CENT, COATING A GLASS SURFACE WITH SAID DISPERSION, AND HEATING THE COATED GLASS SURFACE TO A TEMPERATURE FROM ABOUT 800* F. TO ABOUT 1100* F. TO PRODUCE A STAINED GLASS SURFACE. 